Stringed musical instrument



Dec. 15, 1931. H. H. WHEATLEY 1,836,214

STRINGED MUSICAL INSTRUMENT Filed April 4, 1929 2 Sheets-Sheet 2 la a.

i "at Patented Dec. 15, 1931 PATENT OFFICE HARRY H. WHEATLEY, OI PITTSBURGH, PENNSYLVANIA STBINGED MUSICAL INSTRUMENT Application filed April 4,

This invention relates to improvements in musical instruments, and more particularly to strin ed instruments of the class characterized as anjos and similar instruments.

Present ban'o constructions roduce a metallic ring w ich is objectionab e, and are provided with skin heads which are subject to change of temperature and humidity, which changes produce detrimental effects on the tone of the instrument;

It is a-prime object of this invention to pro vide a stringed musical instrument of the character stated including an air column disposed within the head of the instrument, said column terminating in an expanded opening preferably within the front of said head, whereby the notes of the instrument are amplified and qualified to produce a strengthened and improved tone with a minimum of playing efi'ort.

" It is a further object of my invention to provide a construction to transmit the sound vibrations of the instrument from the strings thereof through a diaphragm to the air col.-

umn, wherein they are am lified and qualified to produce an improve tone.

Other and further objects are, to provide an instrument which will be free from dis- 4 turbances due to changes of temperature and.

humidity; an instrument which may be played with less effort than present constructions; and one which is economical in construction. 7

M invention may be more readily understoo by a reference to the specification taken 'in connection with the accompanying drawin s, wherein:

. ig. 1 is a front view of a stringed instrument embodying my invention;

' Fig. 2, a sectional view on the line IIII of Fig. 1;

Fi 3, a fragmentary sectional view on the line %IIIII of Fig. 1; i Fig. 4, an enlarged sectional view on the line IVIV of Fig. 1, particularly showing the bridge mountin Fi 5, a sectionaT view taken on the line V -of Fig. 1, particularly showing the con- "nection of the diaphragm with the air col- 1929. Serial No. 352,430.

Fig. 6, a sectional view similar to Fig. 2, showing a the outer end of the n eck 6.

The bridge 9 is provided with the usualnotches a for retaining the strings, and is mounted on a cross member 10 having spacedapart depending knife edges 11 thereon. Said knife edges engage a V-slot 12 of a hardened metallic member 13 secured in the face of a tail piece 5a integral with the head 5.

An arm 14, secured at one end to the bridge, is provided, which arm projects downwardly from the bridge 9 through an enlarged opening 15 of said tail piece; it is bent at its lower end and centrally engages a circular diaphragm 16. The diaphragm 16 maybe constructed of thin metal, fiber or mica, or any other suitable material to respond to the vibrations of the strings 7, and is secured peripherally to a hollow sounding box or casing 17 positioned within the head 5. The rear wall of the sound-box is formed with a central opening 18 adapted to communicate with the conduit, generally designated A.

The depth of the head 5 is sufiicient to accommodate the circuitous conduit A. Said conduit affords a comparatively long air passage or column within the head of the instru ment having a definite predetermined ratio of expansion. As shown in Fig. 1, the column extends from the o ening 18 of the soundbox 17, outwardly Eom said sound-box and downwardly toward the back of the head 5,

until one of the walls I) of the conduit merges into the cylindrical wall 19 of the head. The opposite wall 0 terminates short of the wall 19 in an arcuate wall 20, the latter continuing around the enclosure of the head 5 at an increasing distance from the wall 19. In addition to the walls mentioned, the conduit con- 45 may be constructed circular in cross-section,

stituting the air column is formed by top cl the front of the head 5.

inches. ,stopped tube, the length thereof should ,be'

and the back 21 of the head 5, said top being disposed at an increasing distance from the back 21.

The air column terminates in a bell-shaped chamber B having an opening in the plane of a This opened-top chamberis formed by a curved wall 22 having an opening 23 in communication with air column A. The length of said air column is such that its natural frequency shall be lower than the lowest note that can be played on the instrument. This isto avoid excessive strengthening of any note in the range ofthe instrument. This length may be determined by application ofthe laws governing sound vibrations in tubes closed at one end. Accordingly,t'he column will have a natural period of vibration low enough to allow it to respond equally to all notes within the range of the instrument. i

For example, assuming the lowest note to be struck on the instrument is 0 below middleC, which note has a wave length of 106 In a tube closed at one end, ora

equalitoone-fourth the wave length of the fundamental tone, or in the case of 0 below middle 0, 26.5 inches. Hence-the air column will be of sufficient length to respond to G below middle C and all notes of higher frequency.

When a note is struck on'the strings of the instrument, the vibrations set up are imparted to the diaphragm by means of the bridge 9,

cross-member 10, and depending arm 14. The vibrations are then transmitted through the air column A wherein they are amplified and 'equalified, emerging from the opening B in a full, true tone.

' In the form of Figs. 1 to 5 inclusive, I have shown the air column A rectangular in crosssection. Such a construction may be effected by laminated sections glued together.

'However, as in Fig. 6, the air column A and fabricated of pressed fibre sections or the like. It is therefore understood that my invention is not to be limited to an air column of specific cross-section.

It will be noted that this construction concentrates all the sound waves at the front of the head of the instrument and that this amplified tone or volume is directed out wardly and away from the instrument without interruption. 7

Obviously, the bridge 9 being adapted to oscillate on knife edges 11, is very sensitive and must be protected when the instrument is not in'use. Accordingly, I provide a U- shaped 'member 24:, thesides of which are wedge-shaped and may be inserted between the bridge 9 and tail piece 5a of the head 5 to prevent oscillation of the bridge and diaconnected with the conduit, and a string bridge 'on the head operatively connected to the soundbox. v r

2. In a stringed musical instrument of the character specified, a hollow headqhaving a circuitous sound conduit disposedfentirely therein, and. having its dischargeend in the form of a bell-shaped chamber open in the plane of the front of thehe'a'dto throw the sound outwardly therefrom.

3. A stringed musical, nstrument having a hollow head, adiaphragm positioned within thev headto receive vibrations from. the

strings, means providinga sound conduit -v within the head and in communicationwith said diaphragm and adapted to receive the vibrations therefrom, said head having an openchamber disposed at the front thereof and from which the sound isdirected without interruption.

. 4. i A stringed musical instrument having a head, a sound box within the head, a :bridge for thelstrings operatively connected to the sound box, said head having a sound con-;v

'duitleading from the sound box and then extending around the same and opening at the front face of the head. if I 5. A stringed musical instrument having a head, a sound box within the head, said head having a sound. conduit extending around the same and openingfat the front face of the head, a tailpiece on the head atsai-d face extending over the outlet of said conduit, a stringbridge on said tail piece, said conduit leading from'the sound box, and an operative.

connection between the bridge andsoundbox. .6. A stringed musical instrument having a head, asoun'd box within. the head, a bridge for the strings operatively connected to the sound. box, saidheadhaving a sound conduit therein leading frointhe sound box and then extending around the same and opening at the front face of the head,.portions of the walls forming said head also'formingpor-: tions of the walls of said conduit. V

V 7. A. stringed musical instrument having a relatively fiat cylindrical head, a neck extending from the head, a sound box in said head substantially in line with said neck, said head having a sound conduit therein leading from the sound box 'and progressively increasing in cross-sectional area in 'a' direction -aw ay froin the same, said conduit extending completely around the head and opening-at the front face thereof, a tail iece on the head extending over said out et, a strin bridge on said tail piece and adjacent sai sound box, and an operative connection from the bridge to said sound box.

8. The subject matter of claim 7 wherein said bridge is fulcrumed on said tail piece, and wherein said connection comprises an arm extending loosely throu h the tail piece.

In testimon whereof I afl ix my signature.

RRY H. WHEATLEY. 

